Embodiments of the invention relate generally to defect inspection in ferromagnetic parts. More particularly, embodiments of the invention relate to ferromagnetic part inspection using digital magnetic testing.
Inspection of parts to ensure proper fabrication is a necessary step in practically any manufacturing process. Typically, radiography and/or ultrasound are used to inspect the inside of parts, and magnetic particle testing is used to inspect for defects in or near a surface of a part. Magnetic particle testing identifies cracks near a surface of a ferromagnetic part by exposing the part to a magnetic field and flowing small magnetic particles such as soft iron particles across the part, either by air or another fluid. Any defect such as a crack in the part causes the magnetic flux to leave the part, creating two new magnetic poles that attract the small magnetic particles. Hence, accumulation of the magnetic particles in an area on the part indicates a potential defect in the area.